Over the years, Aloni worked as a teacher and as a columnist for several newspapers; published books on political and legal subjects; produced radio programs dealing with legislation and legal procedures (in the wake of one of these, the Office of the Ombudsman was established) and founded the Israel Consumers Council, which she chaired for four years.

Aloni joined the Mapai Party in 1959 and was first elected to Knesset in 1965. In 1973, she left the Labor Party and established Ratz (Citizens Right Movement), a political party advocating electoral reform, separation of religion and state, and a Basic Law protecting human rights.

As Ratz leader, Aloni was elected to Knesset in 1973 and served continiously as head of Ratz until 1992. Before the 1992 elections, Aloni led Ratz into a coalition with Shinui and Mapam to form the new Meretz Party, which won 12 seats in the election. Aloni became Minister of Education, but was forced to resign after a year due to her outspoken statements on matters of religion while she also criticized organized tours by Israeli high school pupils to Holocaustconcentration camps on grounds that such visits were turning Israeli youth into aggressive, nationalistic xenophobes. She was reappointed Minister of Communications and Science and Culture and served until 1996 when she retired from party politics.

Aloni was on the board of the Yesh Din organization, established in March 2005 to "oppose the continuing violation of Palestinian human rights in the Occupied Palestinian Territory".

In 2000, Aloni received the Israel Prize for her lifetime achievements and special contribution to society and the State of Israel and in 2005, she was voted the 57th-greatest Israeli of all time.